Interlocking frame system and components therefor

ABSTRACT

A structural assembly for a recreational vehicle includes a first structural frame member and a second structural frame member with a side wall having a slot for receiving the side wall of the first structural frame member through a notch formed in the side wall and upper wall of the first structural frame member. The upper wall of the second structural frame member is located in the notch when the second structural frame member is engaged with the side wall of the first structural frame member with the slot.

TECHNICAL FIELD AND BACKGROUND

Recreational vehicle (RVs) components, such as walls (including interior walls and sidewalls), floors, and ceilings, are often formed from a laminated panel.

Traditional laminated RV panels are comprised of sheet material layers that are mounted to an aluminum tube frame with foam inserts placed in the frame openings to provide structure, sound dampening, and thermal protection. A typical sandwich panel (from its exterior finish to its interior finish) likely consists of fiber reinforced plastic sheet, a Luan wood sheet or other engineered sheet products, the aluminum frame and foam core, and then a Luan wood sheet with decor paper covering the interior side. This laminated panel configuration is used on RV side wall, floors, rear walls, slide-out walls, slide-out floors, and other smaller structural components used in the RV.

Central to each laminated structure is the aluminum tube frame. The aluminum frame is typically comprised of hollow thin aluminum tubes that are welded together. These frames typically provide enough structure to create the core of the panel, such as the side wall, but ultimately the integrity of the panel is defined by the laminated sandwich that combines the shear strength of its exterior sheets with the core (the frame and the foam inserts) to form a mechanically sound panel, such as a floor or wall. However, given the nature of RVs in that they are pulled her over varied terrain and subject to repeated vibration and shock loading from travel and transportation, the panels tend to take the brunt of the loading and can fail under extreme conditions. Often, these failure can be initiated or at least include the failure of a weld joint.

SUMMARY (P105B)

Accordingly, a structural assembly for a recreational vehicle is disclosed that includes a frame formed from a plurality of metal structural frame members, with hollow portions, that are interconnected in some cases at welded joints, with at least one or more of the welded joints configured such that at least one of the intersecting structural frame members engages the other structural frame member both internally in its hollow space and externally adjacent where it is welded to reduce the stresses at the weld.

Alternately, one or more of the joints are configured such that at least one of the intersecting structural frame member engages the other structural frame members both internally in its hollow space and externally to mechanically couple the two structural frame members together but without the need of a weld.

For example, a first structural frame member is mounted to an exterior surface of a sidewall of a second structural frame member and is configured to engage the interior surface of the side wall to redistribute the stresses at the joint.

In another example, a first structural frame member is mounted to a sidewall of a second structural frame member and is configured to transfer some of the forces to the upper wall of the second structural frame member from the sidewall of the second structural frame member to which the first structural frame member is mounted.

In one embodiment, a structural assembly for a recreational vehicle includes a first structural frame member with a hollow section and a second structural frame member. The side wall of the second structural frame member has a notch, for example, a narrow notch which forms a tab and a slot for receiving the side wall of the first structural frame member through a notch formed in the upper wall of the first structural frame member for receiving the tab into its hollow section. Further, the upper wall of the second structural frame member is located in the notch of the first structural frame member when the second structural frame member is engaged with the side wall of the first structural frame member with the slot wherein the structural assembly forms a component of a recreational vehicle frame.

In one embodiment, the notch of the first structural frame member extends into the side wall of the first structural frame member such that the upper wall of the second structural frame member is coplanar or flush with the upper wall of the first structural frame member when the second structural frame member is engaged with the side wall of the first structural frame member with the slot.

In another embodiment, the notch has a width, and the second structural frame member has a width being approximately equal to the width of the notch of the first structural frame member wherein the notch of the first structural frame member straddles the width of the second structural frame member.

In other embodiments, in any of the above, the side wall of the second structural frame member has a first section on one side of the slot with a first height and a second section on the opposed side of the slot with a second height that is shorter than the first height to thereby form the tab with a shorter height than the first section of the side wall for insertion into the notch of the first structural frame member.

In yet other embodiments, in any of the above, one or both of the first structural frame member and the second structural frame member comprise a hollow tubular structural frame member.

In yet other embodiments, in any of the above, the first structural frame member has a terminal end, and the notch of the first structural frame member extends along the upper wall to the terminal end.

In any of the above, the structural assembly may further include a third structural frame member having an upper wall and a side wall depending from the upper wall of the third structural frame member. The upper wall of the first structural frame member has a second notch, and the second structural frame member has a third notch in the upper wall of the second structural frame member. The side wall of the third structural frame member has a narrow notch that forms a second slot for engaging the side wall of the first structural frame member through the second notch of the first structural frame member and another narrow notch forming a third slot for engaging the side wall of the second structural frame member through the third notch of the upper wall of the second structural frame member.

In any of the above, the first structural frame member is orthogonal to the second structural frame member.

In any of the above, the first structural frame member is formed by first and second joined structural frame members, each of the first and second joined structural frame members having an upper wall forming the upper wall of the first structural frame member and a side wall forming the side wall of the first structural frame member.

For example, the first and second joined structural frame members may be joined in an abutting relationship with a portion of the notch of the first structural frame member being formed in the upper wall of the first joined structural frame member and in the upper wall of the second joined structural frame member. Further, the upper wall of the second structural frame member may be coplanar or flush with the upper walls of the first and second joined structural frame members.

In some embodiments, at least one weld joins the second structural frame member with the first structural frame member. For example, the weld may join the side wall of the second structural frame member with the side wall of the first structural frame member.

In another embodiment, a structural assembly for an recreational vehicle includes a first structural frame member having an upper wall and a side wall depending from the upper wall, with the upper wall having a notch at the side wall. The structural assembly further includes a second structural frame member having an upper wall and a side wall depending from the upper wall, with the upper wall of the second structural frame member having a notch at the side wall of the second structural frame member. The structural assembly also includes a channel-shaped member having an upper plate and a pair of downwardly depending flanges. Each of the flanges having a narrow notch forming a slot to engage with at least one of the side walls of the first and second structural frame members through the notches of the first and second structural frame members wherein the structural assembly forms a component of a recreational vehicle frame.

In a further embodiment, one or both of the notches of the first and second structural frame members extend into a respective side wall of the side walls of the first structural frame member and the second structural frame member, wherein the upper wall of the channel-shaped structural frame member is coplanar or flush with one or both of the upper walls of the first and second structural frame members.

In any of the above, the side wall of the first structural frame member abuts the side wall of the second structural frame member.

Optionally, the structural assembly further includes one or more welds joining the first and second structural frame members, with the weld being adjacent one side of the notch and, optionally, on either side of the notch.

In a further embodiment, the structural assembly further includes a third structural frame member having an upper wall and opposed side walls depending from the upper wall of the third structural frame member. The third structural frame member is disposed between the first and second structural frame members, with the upper wall of the third structural frame member having a notch in the upper wall extending between the opposed side walls. The upper wall of the channel-shaped member extends into the notch of the third structural frame member.

For example, in another embodiment, the slot comprises a first slot, and the opposed flanges have a second slot. The first slot is engaged with the side wall of the first structural frame member and one of the opposed side walls of the third structural frame member. The second slot is engaged with the side wall of the second structural frame member and the other of the opposed side walls of the third structural frame member.

In any of the above, the first, second, and third structural frame members may be parallel to each other.

According to yet another embodiment, a structural assembly for an recreational vehicle includes a first structural frame member having a first upper wall and a pair of opposed first side walls depending from the first upper wall, with the first upper wall having a first notch extending between the opposed first side walls. The structural assembly further includes a second structural frame member having a second upper wall, a bottom wall, and a pair of opposed second side walls extending between the second upper wall and the bottom wall. The bottom wall has a second notch extending between the second side walls, with the second notch being approximately equal in size to the first notch to allow the second structural frame member to straddle and be interlocked with the first structural frame member at the first notch and, further, wherein the second upper wall of the second structural frame member is coplanar or flush with the first upper wall of the first structural frame member.

Optionally, the structural assembly may also include one or more welds joining the first and second structural frame members together wherein the structural assembly forms a component of a recreational vehicle frame. For example, the weld or welds may be located adjacent the first and second notches.

In further embodiments, one or both of the first structural frame member and the second structural frame member comprise a hollow tubular structural frame member.

In yet another embodiment, a frame system for a recreational vehicle includes a plurality of structural frame members arranged in a plane and welded together to form a frame. At least two structural frame members of the structural frame members have a welded joint and have notches formed therein to allow the two structural frame members to be mechanically interlocked at the joint to reduce the size of the weld for the welded joint.

For example, at least two structural frame members may be formed by any one of the above structural assemblies.

Accordingly, a frame is disclosed that can be easily assembled and, further, that can exhibit added rigidity and/or controlled flexibility.

DETAILED DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of an exemplary recreational vehicle;

FIG. 1A is similar view to FIG. 1 but with the outer layers of the various panels removed to show the underlying frames;

FIG. 2 is a side view of a recreational vehicle side panel with the outer layers removed to show the underlying frame and frame members;

FIG. 3 is an enlarged view of detail III-III of FIG. 2 ;

FIG. 4 is an enlarged view of a section of the frame of FIG. 3 ;

FIG. 5 is an enlarged view of another section of the frame of FIG. 3 ;

FIG. 6 is an enlarged fragmentary perspective view of two joined structural frame members;

FIG. 6A is a cross-section view taken along line VIA-VIA of FIG. 6 ;

FIG. 7 is an exploded perspective view illustrating the joint of the two joined members of FIG. 6 ;

FIG. 7A is a top plan view of similar joint to the joint shown in FIG. 7 but with a third structural frame member illustrating optional weld or adhesive locations;

FIG. 7B is a top plan view of the joint of FIG. 7A illustrating adhesive applied to the upper walls of the joined structural frame members;

FIG. 8 is an enlarged fragmentary perspective view of another joint;

FIG. 8A is a cross-section view taken along line VIIIA-VIIIA of FIG. 8 ;

FIG. 9 is an exploded perspective view illustrating the joint of FIG. 8 ;

FIG. 10 is an enlarged fragmentary perspective view of another joint;

FIG. 10A is a cross-section view taken along line XA-XA of FIG. 10 ;

FIG. 11 is an exploded perspective view illustrating the joint of FIG. 10 ;

FIG. 12 is an enlarged fragmentary perspective view of another joint;

FIG. 12A is a cross-section view taken along line XIIA-XIIA of FIG. 12 ;

FIG. 13 is an exploded perspective view illustrating the joint of FIG. 12 ;

FIG. 14 is an enlarged fragmentary perspective view of another joint;

FIG. 14A is a cross-section view taken along line XIVA-XIVA of FIG. 14 ;

FIG. 14B is a cross-section view taken along line XIVB-XIVB of FIG. 14 ;

FIG. 15 is an exploded bottom perspective view illustrating the joint of FIG. 14 ;

FIG. 16 is an enlarged fragmentary perspective view of another joint;

FIG. 17 is an exploded perspective view illustrating the joint of FIG. 16 ;

FIG. 18 is an enlarged fragmentary perspective view of another joint;

FIG. 18A is a cross-section view taken along line XVIIIA-XVIIIA of FIG. 18 ;

FIG. 19 is an exploded perspective view illustrating the joint of FIG. 18 ;

FIG. 20 is an enlarged fragmentary perspective view of another joint;

FIG. 21 is an exploded perspective view illustrating the joint of FIG. 20 ;

FIG. 21A is a similar view to FIG. 21 illustrating the opposed end of one of the structural frame members joined with a third structural frame member using a joint illustrated in FIGS. 6, 6A, and 7 ;

FIG. 21B is an exploded perspective view the structural frame members of FIG. 21A;

FIG. 21C is a cross-section view taken along line XXIC-XXIC of FIG. 21A;

FIG. 22 is an enlarged fragmentary perspective view of another joint;

FIG. 23 is an exploded perspective view illustrating the joint of FIG. 22 ;

FIG. 24 is an enlarged fragmentary perspective view of another joint;

FIG. 25 is an unfolded perspective view illustrating the joint of FIG. 24 ;

FIG. 26 is an enlarged fragmentary perspective view of another joint;

FIG. 27 is an exploded perspective view illustrating the joint of FIG. 26 ;

FIG. 28 is a perspective view illustrating another joint with one or more injection ports;

FIG. 29 is an exploded perspective view of the joint of FIG. 28 ;

FIG. 30 is an enlarged fragmentary perspective view of one of the structural frame members of the joint of FIG. 28 ;

FIG. 31 is an enlarged fragmentary perspective view of another structural frame member of the joint of FIG. 28 ;

FIG. 32 is a similar view to FIG. 28 illustrating the joint reinforced with a foam material;

FIG. 32A is a cross-section taken through line XXXIIA-XXXIIA of FIG. 32 ;

FIG. 32B is a cross-section taken through line XXXIIB-XXXIIB of FIG. 32 ;

FIG. 32C is a similar cross-section to FIG. 32A but illustrating another embodiment of the foam inserts;

FIG. 33 is an end perspective view of the joint of FIG. 32 ;

FIG. 34 is similar view to FIG. 33 ;

FIG. 35 is a perspective view illustrating another joint similar to the joint illustrated in FIG. 28 with multiple injection ports;

FIG. 36 is an end perspective view of the joint of FIG. 35 illustrating one or more foam inserts injected into the joint of FIG. 35 ;

FIG. 37 is an enlarged fragmentary perspective view of another embodiment of the end of one the structural frame members of the joint of FIG. 35 ;

FIG. 38 is an enlarged fragmentary perspective view of yet another embodiment of the end of one the structural frame members of the joint of FIG. 35 ;

FIG. 39 is a cross-section view similar to FIG. 6 illustrating the joint with an insert;

FIG. 40 is a cross-section view similar to FIG. 10A illustrating the joint with an insert;

FIG. 41 is a cross-section view similar to FIG. 12A illustrating the joint with an insert;

FIG. 42 is a cross-section view similar to FIG. 14A illustrating the joint with an insert;

FIG. 43 is a cross-section view similar to FIG. 14B illustrating the joint with an insert;

FIG. 44 is a cross-section view similar to FIG. 18A illustrating the joint with an insert;

FIG. 45 is a cross-section view similar to FIG. 25 illustrating the joint with an insert; and

FIG. 46 is a cross-section view similar to FIG. 21C illustrating the joint with an insert.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 1A, the numeral 10 generally designates a recreational vehicle (RV). Recreational vehicle 10 includes a chassis 12, a plurality of wheels 14, which are mounted to chassis 12, and a plurality of frames 16 that form structural panels (or are covered with panels) to form walls, such as sidewalls 18 and interior walls (not shown), a floor 20 (FIG. 4 ), and/or ceiling/roof 22, which are mounted to the chassis 12 and assembled together form the RV cabin. As will be more fully described below, the frames 16 that form the structural panels (including sidewalls 18, floors 20, and ceiling/roof 22, as well as interior or partitions walls, including accessory compartments frames (not shown)) or to which the structural panels are mounted, may be formed using the frame and frame assembly method described below. Although described in reference to a structural frame for an RV, it should be understood that the frame and frame assembly method described below may be used to form or assemble other frames. For the purposes of this disclosure, the focus of the description will be on how the structural frame members of the frame 16 are joined.

Referring to FIG. 2 , for example, the frame 16 of side wall 18 includes a plurality of horizontal and generally horizontal structural frame members 16 a-16 q, vertical and generally vertical structural frame members 17 a-17 t, a plurality of structural frame members 18 a, 18 b, and 18 c that form connectors, structural frame members 19 a, 19 b, and 19 c that form brace members, and structural frame members S that form offset supports or spacers, which are joined to form the frame 16. Several variations of joining methods are described below, including interlocking of the structural frame members and then optionally welding the structural frame members together. Further, as will be more fully described the structural frame members may be marked, such as by lettering or color coding, to assist in the assembly of the interlocking parts, which may eliminate the need for fixturing.

The terms upper and lower, left, right, vertical and horizontal are just used in reference to the orientation shown in FIG. 2 . Further, it should be understood that additional structural frame members (not illustrated) may form part of the frame, including curved frame members and frame members that are arranged to frame in and reinforce other openings, such as for doors or windows. Therefore, it should be understood that the frame and method of assembling the frame described below may be adjusted and configured to form a variety of different frame configurations.

Referring to FIGS. 3 and 4 , for example, some of the structural frame members may be joined: At right angles (i.e. orthogonal) to each other, such as using a joint J1 (e.g. FIGS. 6, 6A, 7, 16, 17, 21A, 21B, 21C), joint J2 (e.g. FIGS, 8, 8A, and 9), joint J5 (e.g. FIGS. 14, 14A, 14B, and 15 ), joint J7 (e.g. FIGS. 18, 18A, and 19 ), joint J8 (e.g. FIGS. 20, 21, 21A, 21B, 21C), joint J9 (e.g. FIGS. 22 and 23 ), joint 11 (e.g. FIGS. 32 -, 33); joined parallel to each other, such as by joint J3 (e.g. FIGS. 10, 10A, and 11 ), joint J4 (e.g. FIGS. 12, 12, and 13 ); or joined at a non-orthogonal angle to each other, such as joint J6 (e.g. FIGS. 16 and 17 ) or joint J10 (e.g. FIGS. 24 and 25 ), or using a combination of joints (see for example FIGS. 16, 21A, 22, 23, and 26 ), which interlock one or more structural frame members together.

Referring to FIGS. 6, 6A, and 7 , joint J1 is formed by two or more orthogonal structural frame members-for example, a first structural frame member 17 h and a second structural frame member 16 b, which form a T-shaped joint. Though, as described below, a third structural frame member may be attached to first structural frame member 17 h on the opposed side from structural frame member 16 b using the same joint to form a cross-shaped joint. The reference to first and second (or third) in regard to the structural frame members should not be construed to be limiting and is just used to provide a frame of reference.

As understood from FIG. 7 , each of the side walls 30 of the second structural frame member 16 b has a narrow notch 32 in the form of a slot to form tabs 32 a. Slots 32 are sized and configured for receiving the side wall 34 of the first structural frame member 17 h through a notch 36 formed at least in the upper wall 38 of the first structural frame member 17 h, and, optionally, in both the upper wall 38 and the side wall 34 of the first structural frame member 17 h.

Slots 32 extend up into side walls 30 from their lower ends or sides (as seen in FIG. 7 ) to form tabs or fangs 32 a that are used to extend into the notch 36 to thereby engage the side wall 34 from the interior side of the first structural frame member 17 h. Optionally, the height of each of the tabs 32 a may be the same or less than the height of the side walls 30 of first structural frame member 16 b. Thus, each of the side walls of the second structural frame member has a first section on one side of the slot 32 with a first height and a second section on the opposed side of the slot 32 with a second height that is different, e.g. shorter, than the first height to thereby form tabs 32 a with a shorter height than the first sections (e.g. remainder) of the side walls for insertion into the notch in the first structural frame member. As it would be understood with tight tolerances, the shorter the slot 32, the easier it may be to assemble.

Further, the upper wall 40 of the second structural frame member 16 b may extend to the distal end of the second structural frame member. In this manner, upper wall 40 can extend into and be located in the notch 36 when the second structural frame member 16 b is engaged with the first structural frame member 17 h, such as shown in FIG. 6A. As a result, the notch 36 straddles the upper wall at the end of the second structural frame member 16 b. Further, upper wall 40 may be coplanar or flush with the upper wall 38 of first structural frame member 17 h.

In the illustrated embodiment, first structural frame member 17 h and second structural frame member 16 b each have closed rectangular tubular cross-sections with both upper walls 38, 40 and lower walls 42, 44. However, it should be understood that the structural frame members may have open cross-sections, such as L or C shaped cross sections, such as in structural angles or channels, etc. Optionally, in additional to upper wall 40 of second structural frame member 16 b being coplanar with or coplanar or flush and extending into upper wall 38 of first structural frame member 17 h, lower wall 44 may also be coplanar or flush, but adjacent lower wall 42 of first structural frame member 17 h (FIG. 6A).

Optionally, as best understood from FIG. 6A, the illustrated embodiment, the notches 32 and 36 are sized to form a snug fit between the first structural frame member 17 h and the second structural frame member 16 b so that they form a tight, rigid connection. For example, the clearance between the notch 36 and the second structural frame member 16 b may be an air gap, in a range of about 0 to 0.006 inches or in a range of 0 to 0.020 inches. Similarly, the clearance between the notch 32 and the side wall of the first structural frame member 17 h may be an air gap, for example, in a range of about 0 to 0.006 of an inch or in a range of 0 to 0.02 of an inch. Alternately, the notches may be sized to provide a larger gap, for example, in a range of 1/64^(th) of an inch to 1/16^(th) of an inch or greater to provide some flexibility at the joint.

Consequently, when the second structural frame member 16 b is fully engaged with the first structural frame member 17 h, structural frame number 16 b will transfer some of the forces at the joint to the upper wall of the first structural frame member 17 h. Similarly, tabs 32 a will engage the interior surface of the sidewall of the first structural frame member 17 h thereby re-distribute some the stresses from the weld of welds, at the joint when welded, to other portions of the first structural frame member, which has been found to reduce stresses in the weld or welds. In other embodiments, when no welds are provided, this interlocking of the two structural frame members provide a sufficiently rigid joints for the frame, especially when combined with the laminations described below.

Referring again to FIG. 6A, optionally the ends 32 b of tabs 32 a may be rounded or tapered to facilitate insertion, but without significantly reducing the bearing surface between the tabs and the side wall of the first structural frame member 17 h. For example, the tabs 32 a and rounded tapered ends may be sized so that the tabs still contact at least 30% of the height of the side wall or greater of the first structural frame member 17 h. As described below, by providing this internal interface and interlock between the two structural frame members, the stresses on any welds provided, for example, tack welds between the respective side walls of the structural frame members (for example, one of each side of the joint) may be reduced. Further, in some configurations the welds may be eliminated, with the strength of the panel relying on the laminated layers that are applied to both sides of the frame when forming the panels.

Referring to FIGS. 7A and 7B, a third structural frame member 16 b′ may be joined with structural frame member 17 h using the same connection described above in reference to structural frame member 16 b so that together structural frame members 16 b, 16 b′ and 17 h form a cross shaped configuration. As noted below, the structural frame members may be welded together using stitch welding or continuous welds W at their respective sidewalls, including a corner bead weld or welds, such as shown in FIG. 7A . Additionally or in lieu of the corner bead weld or welds, the structural frame members may be joined by one or more surface bead welds, for example on their upper and/or lower walls, such as understood from FIG. 7B. However, as noted above, sufficient strength to the frame may be provided by the laminated layers that are applied to both sides of the frame when forming the panels.

Although illustrated as hollow closed rectangular tubular members, as noted above, it should be understood that either one or both of the first structural frame member and the second structural frame member may have an open section and/or comprise a partially hollow member or a solid structural frame member but with a space formed in at least one of the structural frame members to allow for the internal interface and interlocking of the two members. Further, while illustrated with a rectangular cross-section, the shape of the cross-sections of both or any of the members may be varied.

Referring to FIG. 8 , in another embodiment, namely in joint 2, the upper wall 38′ of the first structural frame member includes two notches 36′, which are spaced apart by a section 36 a′ of upper wall 38′, with each sized to receive a respective tab of tabs 32 a′. Tabs 32 a′ are also formed by narrow notches 32′ in the form of slots that extend up into the opposed side walls 30′ of the second structural frame member. In this embodiment, the upper wall 40′ of the second structural frame member has a forked or bifurcated end 40 a′ so that only portions of the upper wall 40 extend into the notches 36 of the first structural frame member. Further, the portions of the upper wall 40′ that extend into the notches 36′ may be coplanar or flush with the upper wall 38′ of the first structural frame member.

Again, the slots 32′ are configured for receiving the side wall 34′ of the first structural frame member through notches 36′. Optionally, similar to the previous embodiment, the height of each of the tabs 32 a′ may be the same or less than the remainder of the side walls 30′ of the first structural frame member. Additionally, as noted in reference to the above embodiment, and as shown in FIG. 8A, the slots and notches may be sized to form a snug fit connection at the joint or may provide gaps to introduce some flexibility into the joint.

In the above embodiments, the structural frame members are angle at ninety degrees (orthogonal) to each other. Referring to FIGS. 10, 10A, 11, 12, 12A, and 13 , the structural frame members may be parallel, with another structural frame member straddling at least a portion of the parallel structural frame members to interlock them together.

As best seen FIGS. 10, 10A, and 11 , first and second structural frame members 17 r and 17 q are interlocked by a third channel shaped structural frame member 46. Each of the first and second structural frame members 17 r and 17 q has an upper wall 48, 50 and a pair of opposed side wall 52, 54 depending from their respective upper wall 48, 50. In the illustrated embodiment, the inner side walls 52 a, 54 a of each of the first and second structural frame members 17 r and 17 q contact and abut each other—but it should be understood that they may be spaced from each other with the channel shaped structural frame member 46 lengthened to extend and span between the two structural frame members, and further provided with a slot for each of the side walls (such as shown in FIG. 13 ) rather than a shared slot, which is shown in FIGS. 10A and 11 . For example, see structural frame member 18 b (FIG. 2 ).

Each upper wall 48, 50 has a notch 56, 58 at its respective side wall, which optionally extends into the side wall (similar to the previous embodiments). The channel-shaped structural frame member 46 has a web that forms an upper wall 60, and a pair of downwardly depending flanges that form opposed side walls 62. Each of the side walls 62 has a narrow notch in the form of a slot 64, which divides the side walls 62 into two tabs 66 (or fangs). Optionally, each tab is substantially the same size, for engaging and straddling both of the abutting side walls of the first and second structural frame members through the notches 56, 58 (FIG. 10A). Although illustrated as having the same heights, tabs 66 may have different heights to provide different stiffnesses to the joint or simply to facilitate assembly. Further, the widths of the tabs may vary to vary the stiffness of the joint or simply to accommodate different size first and second structural frame members 17 q and 17 r.

Optionally, similar to the first two embodiments, the upper wall of the channel-shaped structural frame member may be coplanar or flush with one or both of the upper walls of the first and second structural frame members. Again, the size of the notches (56, 58, 64) are selected to provide a snug fit connection, such as shown in FIG. 10A, or may be increased to introduce flexibility, such as described above. Additionally, similar to joint J2, notches 56 and 58 may be each formed from a pair of notches (both or just one), with upper wall 60 of member 46 having one or both sides having a forked configuration to extend into the spaced notches.

As best seen FIGS. 12, 12A, and 13 , three parallel structural frame members, such structural frame members 16 i, 16 i, and 16 l, may be interlocked using structural frame member 18 a. Similar to the previous embodiment, structural frame member 18 a straddles between the three structural frame members 16 i, 16 i, and 16 l and is also formed by channel shaped structural frame member 70. Each of the structural frame members has an upper wall 72, 74, 76 and a pair of opposed side wall 78, 80, 82 depending from their respective upper wall 72, 74, 76. In the illustrated embodiment, the inner side walls 78 a and 82 a contact and abut the respective side walls 80 of the middle, second structural frame member 16 i. Again it should be understood that they may be spaced from each other with the channel shaped structural frame member 46 lengthened to extend and span between the spaced structural frame members, and further provided with additional notches to independently engage each of the side walls.

Each upper wall 72, 74, and 76 has a notch 84, 86, 88 at the side wall, which optionally extend into the respective side wall, as seen in FIG. 13 , with sufficient depth to allow member 16 i be coplanar or flush with each of the structural frame members. Further, notch 86 of the central structural frame member 16 i spans the full width of the upper wall 74. As noted, notch 86 optionally extends into each of its side walls 80 at a sufficient depth so that channel-shaped member 70 may traverse and nest in the central structural frame member in notch 86 and similarly extend and nest in notches 84 and 88 of structural frame members 16 i and 16 l so that channel-shaped member 70 nests in all three structural frame members to form a coplanar or flush arrangement.

Channel-shaped member 70 has a web 92, which forms an upper wall (which optionally is coplanar or flush with upper walls 72, 74, and 76), and a pair of downwardly depending flanges 94, which form opposed side walls. Each of the flanges 94 has a pair of narrow notches that form slots 96, which divide the respective side walls into three tabs 98 (or fangs) for engaging the abutting side walls of the first, second, and third second structural frame members through the notches 84, 86, and 88. Similar to the previous embodiment, slots 96 may be sized to engage two side walls, which may or may not have the same thickness.

Although illustrated as having the same heights, tabs 98 may have different heights. Further, the width of each tab may vary—for example, in the illustrated embodiment, the outer tabs 94 a are narrower in width than the central tab 94 b, which spans across the full internal width of the central structural frame member 16 i. However, it should be understood that the central tab 94 b may be at least partially bifurcated with a central narrow notch dividing the central tab into two tabs. For example, the central narrow notch may have the same height as notches 96 or may be shorter or longer and/or narrower or wider.

Optionally, similar to the first two embodiments, as noted, the upper wall of the channel-shaped structural frame member may be coplanar or flush with one, two or all of the upper walls of the first, second, and third structural frame members. For further optional additional details about the tabs and about clearances or gaps between member 18 a and members 16 i, 16 j, and 16 l, reference is made to the above description.

Referring to FIGS. 14, 14A, 14B, and 15 , two structural frame members, such as structural frame members 16 f, 17 h may be arranged so that one structural frame member crosses or transverses the other frame member to form a cross-shaped interlocking joint J5. As best seen in FIG. 15 , the interlocking joint J5 is formed by a notch 102, 104 formed in each structural frame member 16 f, 17 h. One of the notches 104 has extended portions on its opposed sides forming slots 106 (FIGS. 14B and 15 ) to receive the side wall of the other structural frame member to form a central, elongated tab 106 a on each side to extend into the hollow space 102 a of structural frame member 17 h. Each notch 102 and 104 transverses the width of each respective structural frame member and, further, is sized so that the upper wall of each structural frame member is coplanar or flush with the upper wall of the other structural frame member.

Although illustrated with a single, sold tab 106 a on each side of structural frame member 16 f, which extends the full width of the structural frame member 17 h, it should be understood that one or both tabs may be bifurcated by an additional central narrow notch.

In yet other embodiment, as shown in FIG. 16 , two structural frame members, such as structural frame members 19 c and 16 i, may be arranged so that one structural frame member forms a non-orthogonal angle with respect to the other. For example, interlocking joint J6 may be formed by an angled notch 110 in one structural frame member 16 i and a pair of the slots 114 (FIG. 17 ) formed in the opposed side walls of the other structural frame member 19 c, but which are offset from each other so that they can engage the angled side wall and notch of the respective side wall of structural frame member 19 c. Similarly, the opposed end of the angled structural frame member 19 c may have a pair of slots 116 to engage an angled notch 112 formed in a third structural frame member, such as structural frame member 17 s. Structural frame member 17 s may be orthogonal to member 16 i and, further, may be interlocked to member 16 i using joint J1 or J2, described above.

Additional joints may be formed, for example at the ends of two abutting structural frame members, such as first and second structural frame members 17 j and 16 o (FIG. 2 ). For example, referring to FIG. 18 , a notch 118 may be provided that extends through the upper wall 120 of structural frame member 17 j and into side wall 122 and, further, to the terminal end 124 of first structural frame member 17 j. Notch 126, which forms a slot, may be formed in one side wall 128 of second structural frame member 16 o to form a tab 128 a to engage the side wall 122 of the first structural frame member, so that the opposed side wall 130 of the second structural frame member 16 o abuts the distal end 124 of the first structural frame member 17 j (see FIG. 18 ).

Similarly the upper wall 132 of the second structural frame member may extend into the notch 120 and, further, be coplanar or flush with the upper wall 122 of the first structural frame member. Optionally, as noted above, one or more welds may be provided between the respective side walls of the two structural frame members.

Referring to FIGS. 20 and 21 , any one of the structural frame members may be formed as a composite structural frame member 148. For example, in the illustrated embodiment, composite structural frame member 148 may be formed from abutting first and second joined structural frame members 148 a, 148 b. Each of the first and second joined structural frame members 148 a, 148 b has an upper wall and a lower wall 152, 154, and a pair of opposed side walls 158, 160. First and second joined structural frame members 148 a, 148 b are joined by upper and lower tabs 162 formed in the upper and lower walls of one member, e.g. joined structural frame member 148 a, which extend into corresponding notches 164 formed in the upper and lower walls of the other member, e.g. joined structural frame member 148 b. The other structural frame member 150 abuts and straddles the side walls of both joined structural frame members 148 a, 148 b, which forms a joint similar to J1.

Referring to FIG. 21 , structural frame member 150 includes slots 162 a in its opposed side walls 162 that form tabs 162 b that extend into a respective notch 166, 168 formed in each structural frame members 148 a, 148 b at their respective distal ends similar to notches 118, 120 described above.

It should be understood that the various joints described herein may be used with other structural frame members, such as structural frame members S, and further combined with other joints (see FIGS. 21A, 21B, 21C, 22 and 26 ). Further, the shape of the structural frame members may vary and include rectangular, as shown, or rounded cross-sections, including circular. Additionally, while illustrated with closed cross-sections, the structural frame members may have open cross-sections, such as structural angles, channels, half-angles, half tubes, or the like or composite shaped members, for example, with one portion having a closed cross-section and the other extending from the closed-cross-section, such as P-shaped member. Other structural member may have two closed hollow sections, such as side-by-side tubular members.

Referring to FIGS. 21A, 21B, and 21C, as noted above multiple structural frame members may be assembled using two more joints, and further, as will be described below, the joints may be configured so that one joint may have a rigid connection, while another joint may have a flexible connection, for example, to relieve stresses in the overall frame.

For example, structural frame member 16 b may be connected to structural frame member 17 e using joint J1, with notches 32 receiving the side wall 180 of structural frame member 16 b and tab 32 a extended into the interior space 180 a of structural frame member 16 b through notch 181, similar to as described above in reference to FIGS. 6, 6A, and 7 . Structural frame member 17 e in turn may be connected to structural frame member 16 a using joint J8, with notches 162 a receiving the side walls 182, 182″ of structural frame member 16 a and tabs 162 b extended into the interior spaces 182 a′, 182 a″ of structural frame members 16 a′, and 16 a″ through notches 183′, 183″, similar to as described above in reference to FIG. 21 .

In the illustrated arrangement joint J8 may be a rigid joint, especially given that it is formed at the juncture of two abutting structural frame members 16 a′ and 16 a″ that are joined together in a similar manner to members 148 a, 148 b described below in reference to FIG. 20 .

Joint J1 may be formed with greater tolerances between the mating tabs, notches, and/or side walls, as noted above, to provide some flexibility at the joint to thereby reduce stress in the frame. Further, as will be described more fully below, as with all the above joints, inserts may be located internally at one or both joints (J1 or J8) to reinforce the joint or joints or to introduced greater flexibility about one or more axes to modify the degrees of freedom at the respective joint.

Referring to FIG. 22 , joint J9 may be used to join a spacer structural frame member S with two other structural frame members, such as members 17 b and 17 c, with tabs 170 formed on the upper wall of spacer S and corresponding notches formed in the upper walls of members 17 b, 17 c.

Other joints, such as joints J10 shown in FIGS. 22, 24, and 25 , may be formed by forming an angled notch 174, such as a 90 degree notch, in the upper, lower and side walls 176 a, 176 b, 178 a, 178 b of a structural frame member and then folding the structural frame member about the notch (or notches when multiple bends are desired) and, thereafter, welding the bent portions of the member together, such as best understood in FIGS. 24 and 25 . For example, joints J10 may also be suitable for structural frame members 17 c, 16 d, 16 e, 17 f, and 17 t or structural frame members 17 i, 16 g, and 16 hc, which are used for framing a slide out or window.

In any of the above, the structural assembly may further include an additional structural frame member or members joined with other structural frame members using any combination of joints, such joints J1, J3, J6, and/or J10, such as shown in FIGS. 26 and 27 .

In any of the above, at least one weld may join the structural frame members together. For example, the side walls of the structural frame members may be joined together by a weld or welds or an adhesive, for example using a corner bead, including stitch corner beads (FIG. 7A). Optionally, the upper and lower sides of the structural frame members may be welded at their intersections. A full wrap around bead, such as full wrap around weld, may also be used. Further, to adhere the laminations described below, adhesive may be applied to the upper and lower walls of the respective structural frame members (see FIG. 7B). However, the weld or welds may be omitted completely and, instead, rely on the external laminations L (shown only partially in FIG. 2 ) for strength, which are secured to the frame by adhesive, such as described in U.S. patent application Ser. No. 16/346,716, filed on Mar. 18, 2019, owned by Jayco, which is incorporated by reference herein its entirety.

Referring to FIGS. 28-34 , in another embodiment of the various joints described herein, an insert or inserts maybe provided internally to the joint to reinforced the joint internally and, optionally, replace any exterior welds. Further, the joints may be tailored to customize the rigidity or flexibility of the joint as desired, for example to increase or decrease the rigidity or flexibility of the joint about one or more axes. Although illustrated in reference to only some of the joints, it should be understood that any or all of the joints disclosed herein may incorporate the insert described below.

As best seen in FIGS. 28 and 29 , an exemplary joint J11, which is similar to joint J2, includes a three structural frame members 217, 216 a, and 216 b, with structural frame members 216 a and 216 b mounted to structural frame member 217 on opposed sides of structural frame member 217. In the illustrated embodiment, structural frame members 216 a and 216 b are mounted to structural frame member 217 on opposed sides of structural frame member 217 at ninety degree angles (orthogonal) to form a cross-shaped joint. However, it should be understood that the structural frame members 216 a and 216 b may be mounted to structural frame member 217 at non-orthogonal angles, such as shown in joint J6 (FIG. 16 ).

Similar to joint J2, each of structural frame members 216 a and 216 b is coupled to and engaged with a respective side wall 234 of the opposed sidewalls 234 of structural frame member 217 by a pair of tabs 232 a, 233 b. Tabs 232 a, 233 a are formed by slots 232 and 233 that extend up and into side walls 230 and 231 of the respective structural frame members 216 a, 216 b. Similar to the previous embodiments, in the illustrated embodiment tabs 232 a, 233 a have a shorter height than the remainder of the side walls 230, 231, which helps facilitate installation, though they may have the same height as the respective side walls.

Tabs 232 a, 233 a extend into the hollow space inside structural frame member 217 through corresponding pairs of notches 236 formed in structural frame member 217 (on opposed side walls 234) to form a mechanical internal interface with the side walls 234 of structural frame member 217. The size of the notches and slots may vary. For example, in the illustrated embodiment, notches 236 may be sized to be approximately the same thickness as the sidewalls 230, 231 of structural frame number 216 a, 216 b (and the slots 232, 233 may be sized to be approximately the same size as the wall thickness of structural frame member 217) to form a snug fit between the structural frame members so that they optionally form a tight, rigid connection. Further, the terminal edges 240 a, 242 a (FIG. 31 ) of the respective upper walls 240, 242 of structural frame members 216 a, 216 b may be offset from the terminal edges 232 b, 233 b of tabs 232 a, 233 a so that they align with the inner edge 232 c, 233 c of slots 232, 233 and, therefore, abut the side walls 234 of structural frame member 217 at upper wall 238. In this manner, the upper walls 240, 242 of structural frame members 216 a, 216 b are generally coplanar with, but adjacent the upper wall 238 of structural frame number 217.

As noted, structural frame members 216 a, 216 b may form a tight fit connection with structural frame member 217. Alternately, the notches and slots may be sized to allow for some flexibility at one or more selected joints to reduce stresses on the frame. As noted above, some of the panels, for example, the panels that form the side walls, floors, and roof in a recreational vehicle tend to be subject to repeated dynamic loading. Hence, it may be beneficial to make the panel more flexible in areas of the frame that are subjected to increased stress from dynamic loading.

For example, to introduce some flexibility, the clearance between the notch and the side wall of structural frame member 216 a or 216 b (and between the slot and the side wall of structural frame member 217) may be increased (from the above stated exemplary ranges of about 0 to 0.006 inches, 0 to 0.02 inches, or 0 to 0.04 inches) to provide more than an air gap, for example, a gap in a range of 1/64^(th) to 1/32^(th) of an inch, in a range of 1/64^(th) to 1/16^(th) of an inch, or in a range of 1/64^(th) to 1/8^(th) of an inch to provide the desired flexibility and/or to allow the foam, described below, to flow in the gap or gaps to provide some controlled flexibility at the joint. Alternately, the gaps may be provided to ease installation and allow the foam insert described below to flow and, depending on the foam formulation, form an adhesive bond between the structural frame members, as a well as form bearing members (or in some cases springs) to control the rigidity or flexibility of the joint.

Referring to again FIGS. 28 and 29 , one or more expanding foams may be injected into the space formed in one or more of the structural frame members at the joint to internally reinforce the interlock between the joined structural frame members. For example, one of structural frame members, such as structural frame member 217, optionally includes at least one injection port 244 (FIG. 29 ) for injecting one or more expanding foams into the space adjacent the interlocked sections of the structural frame members. For example, a suitable foam may become rigid when cured or may cure or set to a compressible or flexible state to provide a more flexible joint. Optionally, as noted above, the foam may be formulated to provide an adhesive bond between the foam and the structural frame members. Further, a portion of the joint may have one foam injected, and another portion of the joint may have another foam injected so that the stiffness of the joint and other components mounted thereto may be varied.

Referring to FIGS. 32A and 32B, when foam is injected into the hollow space in the structural frame member (e.g. structural frame member 217), for example, through an injection port 231, between tabs 232 a, 233 a, depending on the size of the tabs, the foam may flow between the distal vertical edges 232 b and 233 b of the tabs (FIG. 32A), and further between the inwardly facing sides 232 c, 233 c of tabs 232 a, 233 a (FIG. 32B). Again depending on the height of the tabs, the foam may flow between the lower distal edges 232 d and 233 d of the tabs 232 a, 233 a (FIG. 32B) and the bottom wall of the structural frame member. In this manner, when the foam expands, the foam can form a bearing member that provides restraint in X, Y, and Z axes as shown in FIGS. 32A and 32B. Depending on the foam, the bearing member may be rigid or may be compressible with a varying spring force, again depending on the formulation. When formed from a compressible foam, therefore, the bearing member may also form a spring or springs along the X, Y, and/or Z axis.

Additionally, as noted above depending on the formulation, the foam may form an adhesive bond with the tabs and/or side walls, with the adhesive bond being enhanced depending on the material forming the structural frame members. For example, in polymer based structural frame members a greater bond may be achieved than with aluminum structural frame members, again depending on the formulation of the foam.

As best seen in FIG. 32C, a joint may have two side by side injections ports for injecting two different foams. Referring to FIG. 32C, when foam is injected into the hollow space in the structural frame member (e.g. structural frame member 217 and into joints similar to J1 and J2 except with narrower notches) it may be injected through two ports, e.g. ports 244 a and 244 b, which are provided in the upper wall 238 and between tabs 232 a, 233 a, so that the foams flow into the hollow space between tabs 232 a and 233 a and can form foam inserts 250 and 250′ with different properties. In this manner, when the foams expand, foam insert 250 can form a bearing member that provides restraint in X, Y, and/or Z axes for tab 233 a, while foam insert 250′ can form a bearing member that provides restraint in X, Y, and/or Z axes for tab 232 a as shown in FIG. 32C. For example, one foam may form a rigid insert, while the other may form a flexible, resilient insert.

Additionally, as noted above depending on the formulation, the foam may form an adhesive bond with the tabs and/or side walls, with the adhesive bond being enhanced depending on the material forming the structural frame members. For example, in polymer based structural frame members a greater bond may be achieved than with aluminum structural frame members, again depending on the formulation of the foam.

Suitable foams may include foams from Alumilite of Kalamazoo, Mich. or foams from Smooth-On of Macungie, Pa. For example, suitable foams include ALUMIFOAM, which is a rigid expanding urethane foam; FLEX URETHANE, which is an expanding flexible urethane foam; FOAM IT! RIGID , which is a rigid expanding urethane foam; and SOMA FOAMA, which is an expanding flexible silicone foam.

Referring again to FIGS. 28 and 29 , injection port 244 may be located in upper wall 238 of structural frame member 217 between notches 236 so that port 244 can direct foam 250 into the hollow space in structural frame member 217 between tabs 232 a and between tabs 233 a and side walls 234. Further, depending on the depths and heights of the respective tabs, the foam 250 may flow between the vertical edges 232 b, 233 b of tabs 232 a and 233 a to form a bearing member (when cured or set) between the respective tabs 232 a and 233 a, and also under each lower edge of the tabs.

As best seen in FIG. 32A, in one embodiment, as noted above, the depth and height of each of the tabs allows the foam 250 to flow between the inwardly facing vertical edges 232 b, 233 b of tabs 232 and 233 as well as between the inwardly facing sides 232 d, 233 d and beneath the lower edges 232 e, 233 e of each tab 232, 233. Additionally, as noted above, depending on the size of the clearance or gaps between the respective structural frame members, and the viscosity of the foam, the foam 250 may flow up through the upper wall 238 of structural frame member 217 adjacent upper walls 240, 242 of the structural frame members 216 a, 216 b, such as shown in FIG. 32 .

Referring again to FIG. 29 , structural frame member 217 may include additional injection ports, for example, that direct the flow of foam into adjacent structural frame members or allow two different foams to be injected. For example, structural frame member 217 may have injection ports 246 provided in one or each of the opposed sidewalls 234, between notches 236 and between tabs 232 a and 233 a, to direct the flow of foam 250 into the hollow space provided in structural frame members 216 a and 216 b adjacent side walls 234 of structural frame members 217.

In the illustrated embodiment, each of the structural frame members 217, 216 a and 216 b is a hollow tubular member so that the space provided in each structural frame member is defined by and bounded by their respective upper walls, side walls, and bottom walls. It should be understood that solid or at least partially hollow members may be used to form the respective structural frame members as well.

In this manner, when the foam cures, the internal interface between the tabs and the side walls and bottom wall, for example, is joined either with a connection formed by the foam forming a bearing member adjacent the tabs. For example, when using foam that cures into a rigid form the connection forms a rigid bearing member. When the foam forms a compressible or flexible bearing member adjacent the tabs, the bearing member is flexible and further can have spring properties when the cured or set foam exhibits elastic properties. Additionally, as noted above, one joint (e.g. between structural frame member 216 a and structural frame member 217) may include a rigid foam (when cured) and other the other joint (e.g. between structural frame member 216 b and structural frame member 217) may include a compressible or flexible foam. The location of the differing foams may be controlled in a manner to allow the rigidity or flexibility of the frame to be customized.

For example in one embodiment, the space in structural frame member 217 may be filled with a foam 250 a (FIG. 28 ) that retains some flexibility or compressibility after it cures to allow the structural frame members 216 a, 216 b to flex about structural frame member 217. In contrast, the space in structural frame members 216 a, 216 b may be filled (for example, via injection ports 248 (FIG. 31 )) with a foam 250 b (FIG. 28 ) that becomes rigid upon curing so that when other components are mounted to one or both the structural frame members 216 a or 216 b, the foam can provide rigidity to each connection. For example, ports 248 (see FIGS. 31 and 35 ) may be provided in one or both side walls or upper wall of the respective structural frame members 216 a, 216 b.

In another embodiment, foam 250 may be injected through all the accessible injection ports, such as shown in FIG. 36 , which when cures becomes rigid. Foam 250, therefore not only internally couples the tabs of structural frame members 216 a, 216 b to the interior of structural frame member 217, but also internally couples structural frame members 216 a, 216 b to the exterior of structural frame member 217 to form a very rigid joint. This may be further enhanced if the foam is formulated with adhesive properties.

Optionally, to further enhance the mechanical coupling of the structural frame members together, one or both tabs 232 a, 233 a may include recesses 252 to enhance the mechanical coupling of the foam to the tabs 232 a, 233 a and, hence, to the structural frame members 216 a, 216 b. For example referring to FIG. 37 , recess 252 may be formed in tabs 232 a, 233 a inward of their outer perimeters by transverse through holes or circular indentations 254 formed in the respective tabs.

Alternately, recesses 252 may be formed along the distal edges 232 b, 233 b of one or both of the tabs 232 a, 233 a in the form of cutouts or notches 256 (FIG. 38 ). Again in this manner, the foam will flow into the respective recesses to mechanically couple the foam to the tabs 232 a, 233 a and, hence, structural frame members 216 a, 216 b.

As noted above, any of the above-described joints may be enhanced or modified by the addition of a foam insert or inserts. For example, referring to FIG. 39 , joint J1 (or joint J2) may include an injection port 260 in its upper wall 38 between its opposed ends of notch 36 (and hence between tabs 32 a) to inject a foam insert 250, which can at least partial fill the hollow space between tabs 32 and adjacent tabs 32 a to extend between their distal vertical free edges 32 c and the opposed side wall 34 of structural frame member 17 h. Further, the foam may flow under distal bottom free edges 32 d and extend between edges 32 d and bottom wall 42. In this manner, the foam forms a bearing member to provide reactive forces on tabs 32 a in the X, Y, and Z axes. As noted above, these may be spring forces if the foam is selected to have elastic properties when cured or set.

Optionally, side wall 34 adjacent structural frame member 16 b may include an injection port to direct some of the foam into the hollow space in structural frame member 16 b adjacent side wall 34 between its respective side walls 30. Alternately as described above, structural frame member 16 b may have a port in its upper wall or side wall to inject the same or a different foam to provide an attachment point for another component, including another structural frame member.

Referring to FIG. 40 , joint J3 may include injection ports 264 in upper wall 60 of structural frame member 46 between its opposed side walls 62 (but which straddle the abutting side walls 52 a, 54 a) to inject a foam insert 250 into the hollow spaces in structural frame members 17 q and 17 r. In this manner, the foam can fill the hollow space between side walls 62 and between the distal vertical edges 66 a of tabs 66 and opposed side walls 52 and 54. And depending on the height of the tabs 66, the foam may fill and extend between distal bottom edges 66 b of tabs 66 and bottom walls 49 and 51 of structural frame members 17 q and 17 r. Alternately or in addition, injection ports may be provided in upper walls 48 and 50 of structural frame members 17 q and 17 r.

Referring to FIG. 41 , joint J4 may similarly include one or more foam inserts 250, which may be injected through injections ports provided in structural frame member 18 a (for example by three injection ports provided in upper wall 70) or in structural frame members 16 i, 16 i, and 16 l (for example by three injection ports in upper walls 72, 74, and 76). In this manner, the foam can fill the hollow space between side walls 94 and between the distal vertical edges 94 c of tabs 94 a and opposed side walls 78 and 82. And depending on the height of the tabs 94 a, 94 b, the foam may fill and extend between distal bottom edges 94 d, 94 e of tabs 94 a, 94 b and bottom walls 73, 75, and 77 of structural frame members 16 i, 16 i, and 16 l. Alternately or in addition, injection ports may be provided in upper walls 72, 74, and 76 of structural frame members 16 i, 16 i, and 16 l.

Referring to FIGS. 42 and 43 , joint J5 may similarly include one or more foam inserts 250, which may be injected through an injections port 270 provided in the upper wall or bottom wall of structural frame member 16 f or 17 h located between their respective side walls and between the opposed ends of notches 102 and 104. Further, to allow the foam to flow into the hollow spaces adjacent their respective abutting side walls, as shown in FIGS. 42 and 43 , side wall 272 of structural frame member 17 h may include an injection port 274. Further, when tabs 106 a are shorter that the side walls of structural frame member 17 h, the foam may flow under the tabs 106 a into the adjacent hollow space (see FIG. 43 ).

In this manner, the foam can form a bearing member between the distal bottom free edges 106 b of tabs 106 a and the bottom wall of structural frame member 17 h and between the vertical edges of tabs 106 a and the side walls of structural frame member 17 h when the slots 106 have more than an air gap to allow foam to flow into the slots adjacent the edges of tabs 106 a.

Referring to FIG. 44 , joint J7 may also include a foam insert or inserts similar to joint J1 and J3, with an injection port provided in either upper wall 120 or upper wall 132 of structural frame members 17 j or 16 o, or side walls 122 or 130.

Referring to FIG. 45 , a foam insert 250 may also be used in joint J10, which may be particularly suitable for foam with adhesive properties to enhance the joint one the structural frame member is bent and folded as shown in FIG. 24 . Again, one or more injection ports may be provided in the upper, lower and/or side walls 176 a, 176 b, 178 a, 178 b of the structural frame member so that the foam forms a bearing member inside the hollow spaces of the two sectioned parts of the structural frame member to resist bending and torsion at the joint to help keep the joint in its folded configuration.

As described above, two different foams may be used to provide different joint characteristics. For example, structural frame members may be connected using two or more joints, including two or more different joints, with one joint being provided with a rigid foam insert and another joint being provided with compressible and, optionally elastic, foam insert.

For example, referring to FIG. 46 , three structural frame members are arranged and connected in an H frame configuration with a central structural frame member 17 e connected to structural frame member 16 b using joint J1 on one end connected to structural frame member 16 a using joint J8. Joint 1, for example, may include a foam insert 250 formed from one foam, and joint J8 may include a foam insert 250′ formed from a different foam that joint J1. In the illustrated embodiment, joint J1 is provided with a rigid foam insert, while joint J is provided with greater gaps and a flexible, foam insert, and optionally with elastic properties to allow joint J1 to flex under certain loading conditions, such as dynamic loading above a certain threshold.

As noted above, the structural frame members forming the frames described above, may be formed from metal, such as aluminum, or may be formed from a polymer or a composite material. Further, while shown as having rectangular or square hollow closed cross-sections, the shape of the structural frame members may vary and, further, may have solid sections or open sections, and may have a composite section—one part closed and the other part open or solid. The joints may be orthogonal or angled as shown, with angle varying from zero degrees to 90 degrees. Further, as noted, the joints may have a weld or an adhesive on their exterior surfaces. Additionally, the joints may have air gaps or gaps that allow some degree of freedom along or about one or more axes.

It should be understood that in any of the above joints, depending on the forces and vibrations at the joint, welds may be used or omitted. Further, foam inserts may be used to reinforce the joint and/or provided added flexibility when desired. Accordingly, the structural assemblies described herein may provide enhanced connections between the respective structural frame members to varying degrees and, further, provide a greater joining interface or surface to hold the members together, which may provide a greater distribution of load across the joined members. As described above, in some embodiments welding may be used in which case the stresses in the welds may be reduce. In other cases, the welds may be eliminated, which can avoid burn through or gouging that can occur during welding. 

We claim:
 1. A structural assembly for a recreational vehicle, said structural assembly comprising: a first tubular structural frame member having a first wall, a second wall spaced from and parallel to said first wall, and third and fourth side walls depending from and extending between said first and second walls, and said first wall having a notch extending into said first wall and said third side wall; and a second tubular structural frame member having a first wall and a second wall spaced from and parallel to said first wall of said second tubular structural frame member, said second tubular structural frame member further having third and fourth side walls depending from and extending between said first and second walls of said second tubular structural frame member, said third and fourth side walls of said second tubular structural frame member each having a slot receiving and third side wall of said first tubular structural frame member through said notch, and said first wall of said second tubular structural frame member being located in said notch and filling said notch wherein only an air gap is formed between said second tubular structural frame member and said first tubular structural frame member when said second tubular structural frame member is engaged with said third side wall of said first tubular structural frame member with said slot to provide a tight rigid joint between the first and second tubular structural frame members.
 2. The structural assembly according to claim 1, wherein said first wall of said second structural frame member is coplanar with said first wall of said first structural frame member when said second structural frame member is engaged with said third side wall of said first structural frame member with said slot.
 3. The structural assembly according to claim 1, wherein said notch has a width, and said second structural frame member has a width being approximately equal to said width of said notch wherein said notch straddles the width of the second structural frame member.
 4. The structural assembly according to claim 1, wherein said third side wall of said second structural frame member has a first section on one side of said slot with a first height and a second section on the opposed side of said slot with a second height that is shorter than the first height to thereby form a tab with a shorter height than the first section of said third side wall of said second structural frame member for insertion into the notch.
 5. The structural assembly according to claim 1, wherein one or both of said first structural frame member and said second structural frame member comprise a hollow tubular structural frame member.
 6. The structural assembly according to claim 1, wherein said first structural frame member has a terminal end, and said notch extend through said first wall of said first structural frame member to said terminal end.
 7. The structural assembly according to claim 1, further comprising: a third structural frame member having first wall and a side wall depending from said first wall of said third structural frame member; a second notch in said first wall of said first structural frame member spaced from said first notch; said second structural frame member having a third notch in said first wall of said second structural frame member extending into said third side wall of said second structural frame member; and said side wall of said third structural frame member having a second slot engaging said third side wall of said first structural frame member through said second notch and a third slot engaging said third side wall of said second structural frame member through said third notch of said first wall of said second structural frame member.
 8. The structural assembly according to claim 1, wherein said first structural frame member is orthogonal to said second structural frame member.
 9. The structural assembly according to claim 1, further comprising at least one weld joining said third side wall of said second structural frame member with said third side wall of said first structural frame member and wherein said structural assembly forms a component of a recreational vehicle frame.
 10. A structural assemble for a recreational vehicle, said structural assembly compromising: a first structural frame member having an upper wall and a side wall depending from said upper wall, and said upper wall having a notch at said side wall; and a second structural frame member having an upper wall and a side wall depending from said upper wall, said side wall of said second structural frame member having a slot receiving said side wall of said first structural frame member through said notch, and said upper wall of said second structural frame member being located in said notch when said second structural frame member is engaged with said side wall of said first structural frame member with said slot, wherein said first structural frame member is formed by first and second joined structural frame members, each of said first and second joined structural frame members having an upper wall forming said upper wall of said first structural frame member and a side wall forming said side wall of said first structural frame member.
 11. The structural assembly according to claim 10, wherein said first and second joined structural frame members are joined in an abutting relationship with a portion of said notch of said first structural frame member is formed in said upper wall of said first joined structural frame member and in said upper wall of said second joined structural frame member, and said upper wall of said second structural frame member coplanar with said upper walls of said first and second joined structural frame members.
 12. A structural assembly for a recreational vehicle, said structural assembly comprising: a first structural frame member having an upper wall and a side wall depending from said upper wall, said upper wall having a notch at said side wall; a second structural frame member having an upper wall and a side wall depending from said upper wall, said upper wall of said second structural frame member having a notch at said side wall of said second structural frame member; and a channel-shaped member having an upper plate and a pair of downwardly depending flanges, each of said flanges having a slot engaged with at least one of said side walls of said first and second structural frame members through said notches wherein said structural assembly forms a component of a recreational vehicle frame.
 13. The structural assembly according to claim 12, wherein one or both of said notches extend into a respective side wall of said side walls of said first structural frame member and said second structural frame member, wherein said upper wall of said channel-shaped structural frame member is coplanar with one or both of said upper walls of said first and second structural frame members.
 14. The structural assembly according to claim 12, wherein said side wall of said first structural frame member abuts said side wall of said second structural frame member.
 15. The structural assembly according to claim 14, further comprising one or more welds joining said first and second structural frame members, said weld being adjacent one side of said notch and optionally on either side of said notch.
 16. The structural assembly according to claim 12, further comprising: a third structural frame member having an upper wall and opposed side walls depending from said upper wall of said third structural frame member, said third structural frame member disposed between said first and second structural frame members, said upper wall of said third structural frame member having a notch in said upper wall extending between said opposed side walls, and said upper wall of said channel-shaped member extending into said notch of said third structural frame member.
 17. The structural assembly according to claim 16, wherein said slot comprises a first slot, and said opposed flanges have a second slot, said first slot engaged with said side wall of the first structural frame member and one of said opposed side walls of said third structural frame member, and said second slot engaged with the side wall of the second structural frame member and the other of said opposed side walls of said third structural frame member.
 18. The structural assembly according to claim 17, wherein said first, second and third structural frame members are parallel to each other.
 19. A structural assembly for a recreational vehicle, said structural assembly comprising: a first structural frame member having a first upper wall and a pair of opposed first side walls depending from said first upper wall, said first upper wall having a first notch extending across said first upper wall and extending into said opposed first side walls; a second structural frame member having a second upper wall, a bottom wall, and a pair of opposed second side walls extending between said second upper wall and said bottom wall to thereby form a structural beam, said bottom wall having a second notch extending across said bottom wall and extending into said second side walls, and said second notch being approximately equal in size to said first notch to allow said second structural frame member to straddle and be interlocked with said first structural frame member at said first notch wherein said second upper wall of said second structural frame member is coplanar with said first upper wall of said first structural frame member; said first or second opposed side walls each including a pair of slots on opposed sides of each respective notch of said first and second notches to receive the opposed side walls of the other of said first or second opposed side walls in said pair of slots; and a weld joining said first and second side walls together wherein said structural assembly forms a component of a recreational vehicle frame.
 20. The structural assembly according to claim 19, wherein said weld is located adjacent said first and second notches.
 21. The structural assembly according to claim 19, wherein one or both of said first structural frame member and said second structural frame member comprise a hollow tubular structural frame member. 